1. Field of the Invention
This invention relates to a high-speed transmission connector for use in a communication device or the like, which is suitable for transmission of high-frequency signals.
2. Description of the Prior Art
FIG. 11 shows a conventional high-speed transmission connector in front view, while FIG. 12 shows the same in rear view. FIG. 13 is a cross-sectional view taken on line XIIIxe2x80x94XIII of FIG. 11. FIG. 14 shows the FIG. 11 transmission connector in side view. FIG. 15 is a cross-sectional view taken on line XVxe2x80x94XV of FIG. 14, while FIG. 16 is a cross-sectional view taken on line XVIxe2x80x94XVI of FIG. 14. FIG. 17A is a side view of an upper-section shield contact, FIG. 17B a front view of the same, and FIG. 17C and FIG. 17D are a rear view and a plan view, respectively. Further, FIG. 18A is a side view of a middle-section shield contact, FIG. 18B a front view of the same, and FIG. 18C and FIG. 18D are a rear view and a plan view, respectively.
The conventional connector includes an insulator 110 and a shield casing 120 attached to the insulator 110 in intimate contact with the same.
The insulator 110 holds signal contacts 130a, 130b, . . . (generically designated by reference numeral 130), the upper-section shield contact 140 and the middle-section shield contact 150.
A location plate 160 is fixedly secured to a rear face of the insulator 110 e.g. by press-fitting or the like. The location plate 160 has a lattice of contact through holes 161 formed therethrough. The contact through holes 161 are formed with respective tapered faces for guiding the contacts 130, 140, 150.
The signal contacts 130 and the shield contacts 140, 150 each have an intermediate portion thereof bent at a right angle (see FIGS. 17A and 18A).
Each of the signal contacts 130 and the shield contacts 140, 150 has one end portion thereof inserted through a corresponding one of the contact through holes 161 and held by the location plate 160.
The front face (right side, as viewed in FIG. 14) of the insulator 110 is formed with receiving holes 111 for connection with a mating connector, not shown.
Each of the signal contacts 130 and the shield contacts 140, 150 has the other end thereof disposed in a corresponding one of the receiving holes 111.
The signal contacts 130a, 130b and the signal contacts 130c, 130d are arranged on opposite sides of the shield contact 140 (see FIG. 13).
The signal contacts 130e, 130f and the signal contacts 130g, 130h are arranged on opposite sides of the shield contact 150.
The signal contacts 130a, 130b adjacent to each other are used to transmit paired signals.
In the above connector, however, since respective portions (designated by an arrow A in FIG. 14) of the contacts 130, 140 are, exposed between the insulator 110 and the location plate 160, characteristic impedances of the contacts, which are determined by inductances and capacitances of the respective contacts, become higher than a characteristic impedance applied to a transmission system for transmitting high-frequency signals and high-speed signals, which causes a mismatch between the characteristic impedances.
Further, the characteristic impedances of an associated pair of signal contacts 130 (e.g. the signal contacts 130a, 130b) differ from each other due to difference in distance between the shield contacts 140, 150 and the respective corresponding signal contacts 130 (the impedance of a contact arranged at a location farther from a corresponding shield contact Is higher than that of a contact arranged at a location closer to the shield contact), which causes variations in high-frequency characteristics of the associated pair of signal contacts .
As a result, losses of high-frequency signals and high-speed signals due to the mismatch between the characteristic impedances are increased, and hence transmission characteristics are considerably degraded.
It is an object of the invention to provide a high-speed transmission connector which is capable of maintaining a match between characteristic impedances and achieving excellent transmission characteristics for transmission of high-frequency signals and high-speed signals.
To attain the above object, the present invention provides a high-speed transmission connector comprising:
an insulator;
at least one shield contact held by the insulator;
at least one pair of signal contacts held by the insulation and each arranged on respective opposite sides of a corresponding one of the at least one shield contact; and
a shield member enclosing the at least one pair of signal contacts and arranged continuous with the shield contact.
According to this high-speed transmission connector, since portions of the signal contacts and the shield contact, which are exposed in the prior art, are enclosed by the shield member continuous with the shield contact, the signal contacts are shielded, whereby characteristic impedances of the respective signal contacts are reduced and become equal to each other.
Preferably, the shield member is integrally formed with the shield contact.
According to this preferred embodiment, since the shield member is integrally formed with the shield contact, it is possible to prevent an increase in number of component parts of the connector.